SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '74cfb0417ccf349d57791f742b469f1eb395ddc81374eb89a8f4ff05c3dcdf57' 
  AND token = 'f3nlCG4xzRuEk1PUaPaGeo+REqV/1EJe4AWpBRXvYjU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}